Page 327 - Handbook of Electrical Engineering
P. 327
314 HANDBOOK OF ELECTRICAL ENGINEERING
• Reverse active power (32).
• Negative phase sequence (46).
• Stator earth fault current (51 G) and (64).
• Over terminal voltage, (59) Note 1.
• Under terminal voltage, (27) Note 1.
• Overfrequency, (81) Note 2.
• Underfrequency, (81) Note 2.
• Winding temperature (26).
Note 1: These can be combined in one voltage relay.
Note 2: These can be combined in one frequency relay.
A typical scheme that contains most of these relays is shown in Figure 12.2.
12.2.2 Overcurrent
12.2.2.1 Response of a generator to a major fault
When a major fault occurs externally from the generator but near to the generator stator terminals or
near its switchgear, two reactions take place:-
Figure 12.2 Protective devices for a high voltage generator.
